How to use

readSpans

method

in

zipkin.internal.JsonCodec

 @Override public Iterable<Span> call(byte[] bytes) throws Exception {
  logInitializer().run();
  if (bytes.length == 0) return Collections.emptyList();
  try {
   if (bytes[0] == '[') {
    return Codec.JSON.readSpans(bytes);
   } else {
    if (bytes[0] == 12 /* TType.STRUCT */) {
     return Codec.THRIFT.readSpans(bytes);
    } else { // historical kafka encoding of single thrift span per message
     return Collections.singletonList(Codec.THRIFT.readSpan(bytes));
    }
   }
  } catch (RuntimeException e) {
   log.warn("unable to decode spans", e);
   return Collections.emptyList();
  }
 }
}

 /**
  * Conditionally decodes depending on whether the input bytes are encoded as a single span or a
  * list.
  */
 static List<Span> fromBytes(byte[] bytes) {
  // In TBinaryProtocol encoding, the first byte is the TType, in a range 0-16
  // .. If the first byte isn't in that range, it isn't a thrift.
  //
  // When byte(0) == '[' (91), assume it is a list of json-encoded spans
  //
  // When byte(0) <= 16, assume it is a TBinaryProtocol-encoded thrift
  // .. When serializing a Span (Struct), the first byte will be the type of a field
  // .. When serializing a List[ThriftSpan], the first byte is the member type, TType.STRUCT(12)
  // .. As ThriftSpan has no STRUCT fields: so, if the first byte is TType.STRUCT(12), it is a list.
  if (bytes[0] == '[') {
   return Codec.JSON.readSpans(bytes);
  } else if (bytes[0] == 12 /* TType.STRUCT */) {
   return Codec.THRIFT.readSpans(bytes);
  } else {
   return Collections.singletonList(Codec.THRIFT.readSpan(bytes));
  }
 }
}

 /**
  * Conditionally decodes depending on whether the input bytes are encoded as a single span or a
  * list.
  */
 static List<Span> fromBytes(byte[] bytes) {
  // In TBinaryProtocol encoding, the first byte is the TType, in a range 0-16
  // .. If the first byte isn't in that range, it isn't a thrift.
  //
  // When byte(0) == '[' (91), assume it is a list of json-encoded spans
  //
  // When byte(0) <= 16, assume it is a TBinaryProtocol-encoded thrift
  // .. When serializing a Span (Struct), the first byte will be the type of a field
  // .. When serializing a List[ThriftSpan], the first byte is the member type, TType.STRUCT(12)
  // .. As ThriftSpan has no STRUCT fields: so, if the first byte is TType.STRUCT(12), it is a list.
  if (bytes[0] == '[') {
   return Codec.JSON.readSpans(bytes);
  } else if (bytes[0] == 12 /* TType.STRUCT */) {
   return Codec.THRIFT.readSpans(bytes);
  } else {
   return Collections.singletonList(Codec.THRIFT.readSpan(bytes));
  }
 }
}

  byte[] deserializableBytes = (compressPayload) ? unGzip(receivedPayloadBytes) : receivedPayloadBytes;
  List<zipkin.Span> receivedSpans = Codec.JSON.readSpans(deserializableBytes);
  assertThat(receivedSpans).isEqualTo(sentSpans);
} finally {